I have a portable generator 6.5 kVA w/ 7500 watts single phase 120/240 type. It has a pair of 120 gfic outlets and one 4 twist type 240 outlet. I would like additional input on how to wire to house panel (100amp)w/ out a transfer switch. Understand during outage one would operate it in a standard mode ;but w/ main breaker in OFF position. Will this run my ac unit and refridge? What Wire type (3 or 4 wire) and plug type is needed to accomplish this ? Thank you for any input.

You DO NOT do this!! What you propose is stupid, unsafe and ILLEGAL!

There are reasons EVERY power company web site has warnings about illegally backfeeding your service.

Get a transfer switch, transfer panel, or main breaker interlock, or just use extension cords to power up the appliances you need.

Clarification:

Main Breaker Interlock

Prevents backfeeding to the utility. It interlocks the main breaker and the breaker for the generator so that both cannot be on at the same time.

Second:
You will need a generator input connector mounted on the outside of your house.

Third:
When using the generator powering the house, the neutral to ground bond in the generator should be removed. When independently operating the generator, it should be present.